The present invention relates to a method for the manufacture of a photoelectric charging device. In particular, the present invention relates to a fully automated process of placing and electrically connecting a solar chip on a printed circuit board to provide supplemental photoelectric charge to portable & non portable electronic devices.
It is well known that there is a need for battery charging alternatives for use by portable electronics and more specifically, rechargeable communication devices. One solution that has satisfied this need is the use of micro-solar assemblies for providing supplemental photoelectric charge for the purpose of solar charging these device's batteries. Typically, a micro-solar assembly is comprised of a small light gathering area made of at least one solar chip and diode in series to provide positive current flow and prevent the back flow of current in low light. Preferably, these solar chips are the result of dicing pieces of a standard 4".times.4" solar cell. The dicing of solar cells into solar chips allows a manufacturer to create micro solar assemblies of specific sizes.
To date, the process of fabricating micro-solar assemblies is labor intensive requiring many steps to be done by hand. The past process of fabrication consisted of individually soldering the diced chips twice for the positive and negative connections; placing the diced chips on a backing to create a placement and to provide structural integrity, and then sealing the diced chips to the backing by a two part UV resistant polymer to provide impact resistance.
Individual hand soldering of solar chips is a time consuming process fraught with human error and requiring skilled labor to be successful. A micro-solar assemblies require two solder connections for each solar chip as well as numerous gangly connections to ancillary devices and the electronic device being charged. Therefore, there is a need for the removal of hand soldering to be replaced by an automation technique which will greatly reduce the cost and time associated with this process step.
Next, backing substrates or plates, while necessary and simple in nature, are full of inherent problems. These problems arise with the need for exact placement of the small solar chips by human hand onto the backing substrates, a technique which provides inadequate alignment. Also, there is the problem of getting the solar chips to lay flat on the backing substrate or plate. The bottom solder joint generally has some thickness and this thickness varies because of the hand operation. When the chips do not sit flat they are subject to breakage from the fulcrum created underneath each chip by the solder joint. Therefore, there is a need for an automated process that will provide the exact alignment and placement of the solar chips while simultaneously having the solar chips lay as flat as possible on its plate during the bonding process.
Additional problems arise from the differential temperature expansion and contraction between the solar cell and the backing plate which result in the breaking of chips and/or their electrical connections. While temperature resistant plates can be used, there is a need to bond the cell to the plate to act as a single unit which does not result in breakage of the electrical connection. Lastly, problems arise during the polymer coating phase from the nature of using two part viscous polymers. The curing times, air entraining properties, and bonding properties make quick production style usage problematic.
While some of the aforementioned methods are desirable, none of the methods or apparatus describe above provide an automated process which provides a consistently high quality, low cost micro-solar array for use in charging portable electronic devices. The subject invention herein solves all of these problems in a new and unique manner which has not been part of the art previously.